Thyroid health supplements: what helps and what to avoid

Low thyroid function can sap your energy, make weight loss feel impossible, and mess with mood. Supplements sometimes help, but they can also interfere with prescription thyroid meds. This page gives clear, practical advice so you can pick supplements that may help and avoid ones that cause trouble.

Supplements that may help

Selenium — Small clinical trials show selenium can reduce thyroid antibody levels in autoimmune thyroiditis (Hashimoto’s). Typical doses are 100–200 mcg daily. Don’t double up with multivitamins that already contain selenium.

Myo-inositol — Research has found myo-inositol (often paired with selenium) can improve thyroid function markers in subclinical hypothyroidism and support women with thyroid-related fertility issues. Common dosage in studies is 600 mg twice daily when combined with 83 mcg selenium.

Iodine — Iodine is essential for thyroid hormone production, but more is not always better. If you have Hashimoto’s or live in an area with sufficient iodine, extra iodine can worsen autoimmunity. Only consider iodine when a deficiency is documented by a doctor.

Vitamin D — Low vitamin D levels are common in people with autoimmune thyroid disease. Replacing vitamin D can improve overall health and may help immune balance. Aim for testing first; many people need 1,000–4,000 IU daily depending on blood levels.

Iron, zinc, and B vitamins — Iron deficiency can blunt thyroid treatment response. Zinc supports thyroid hormone conversion. If tests show low levels, supplements can help. Take iron at a different time from levothyroxine.

How to use supplements safely

Timing matters. Levothyroxine should be taken on an empty stomach 30–60 minutes before food. Minerals like calcium, iron, and high-dose magnesium or zinc interfere with absorption, so keep them at least 4 hours apart.

Test before you guess. Get TSH, free T4 and, if relevant, thyroid antibodies and nutrient labs (iron, ferritin, vitamin D) before starting supplements. That points to what you actually need and prevents overdosing.

Watch doses and combos. Don’t stack multiple products that contain the same nutrient. For example, combining a thyroid formula with a multivitamin may push selenium or iodine above safe limits.

Talk to a professional. If you’re on levothyroxine, tell your clinician about any new supplement. Small trials support selenium and myo-inositol in specific cases, but your lab results and symptoms should guide use.

Short checklist: 1) Get labs first. 2) Start one supplement at a time. 3) Space minerals away from thyroid meds. 4) Avoid high-dose iodine unless deficient. 5) Recheck labs after 8–12 weeks.

Want more details on meds and monitoring? See our piece on why you need to keep an eye on levothyroxine levels for practical tips on testing and dose checks.